Most industrial processes and systems usually include sensors and alarm systems in which measured signals are monitored. Such industrial processes and systems can include, for example, conventional and nuclear power plants, pulp and paper plants, petroleum refineries, chemical and bio-chemical plants, and so forth. Examples of other industrial processes or systems include, for example, aerospace facilities, aircraft cockpits, medical intensive care units, and various government and military command locations. In these processes or systems, a large number of automated alarms are typically utilized, which are established to monitor one or more measured values, and are used to activate a warning signal if the value(s) goes beyond at least one limit, typically outside an alarm interval defined by a lower alarm limit and an upper alarm limit.
Identifying periodic patterns during events occurring over a period of time (e.g., days, weeks or months) can be useful for identifying actions that can improve manufacturing process efficiency and safety, especially when the events are process alarms. For this purpose, an alarm and event viewer may be provided in a table arrangement for the user (e.g., operator) to view. The table arrangement in such conventional alarm and event viewers is a row-by-row account of alarm and event activity, which are essentially text-based lists with each entry including a date, time and event identification (ID). A user (e.g., an operator) must read and decode the text-based information in each row to try identify event occurrence patterns, making it difficult to identify, for instance, event occurrence patterns having hourly or daily periods.